OVERVIEW

The implementation of harmonic filters has become an essential element of electric power networks. With the advancements in technology and significant improvements of power electronic devices, utilities are continually pressured to provide high-quality and reliable energy. Power electronic devices such as computers, printers, fax machines, fluorescent lighting, and most other office equipment generate harmonics. These types of devices are commonly classified as nonlinear loads. These loads (e.g., rectifiers, inverters) create harmonics by drawing current in short pulses rather than in a sinusoidal manner.

Harmonic currents and the associated harmonic powers must be supplied from the utility system. The major issues associated with the supply of harmonics to nonlinear loads are severe overheating: increased operating temperatures of generators and transformers degrade the insulation material of their windings. If this heating were continued to the point at which the insulation fails, a flashover would occur. This would partially or permanently damage the device and result in loss of generation or transmission that could cause blackouts. Impacts of harmonics on the insulation of transformers and electrical machines are discussed in Chapter 6.

One solution to this problem is to install a harmonic filter for each nonlinear load connected to the power system. There are different types of harmonic filters including passive, active, and hybrid configurations [1 8]. The installation of active filters proves indispensable for solving power quality problems in distribution networks such as the compensation of harmonic current and voltage, reactive power, voltage sags, voltage flicker, and negative-phase sequence currents. Ultimately, this...